1. Field of the Invention
Prefabricated floor boards provided with tongue and groove at the edges are quite common nowadays. These can be installed by the average handy man as they are very easy to install. Such floors can, for example, be constituted of solid wood, fibre board or particle board. These are most often provided with a surface layer such as lacquer, or some kind of laminate. The boards are most often installed by being glued via tongue and groove. The most common types of tongue and groove are however burdened with the disadvantage to form gaps of varying width between the floor boards in cases where the installer hasn't been thorough enough. Dirt will easily collect in such gaps. Moisture will furthermore enter the gaps which will cause the core to expand in cases where it is made of wood, fibre board or particle board, which usually is the case. The expansion will cause the surface layer to rise closest to the edges of the joint which radically reduces the useful life of the floor since the surface layer will be exposed to an exceptional wear. Different types of tensioning devices, forcing the floor boards together during installation can be used to avoid such gaps. This operation is however more or less awkward. It is therefore desirable to achieve a joint which is self-guiding and thereby automatically finds the correct position. Such a joint would also be possible to utilise in floors where no glue is to be used.
2. Description of the Invention
The different types of floor panels caught by the description above are all of the type known as floating floor installations. This means that the panels are attached, one to the other but not to the subjacent subfloor. Such a floating floor is allowed to expand and contract with change in moisture content. Such changes in moisture content will demand that there is sufficient space between the circumscribing edge of the floor installation and the surrounding walls. These space are normally covered by mouldings but in larger rooms and long corridors it will be necessary to install so called dilatation profiles to take up the naturally occurring movement in the floating floor. These dilatation devices are normally bulky and aren't always a welcome feature in the interior design. In fact, in some markets they are known as “speed bumps”. It is also important to take good care of items like water pipes for radiators coming up through the floor. It has occurred that such pipes have been caused to leak by expanding floating floor installations.
Another known problem is when for example a heavy book shelf is placed in one end of a room and a heavy piano is placed on the opposite end of the room after a warm wet summer. Once the moisture content in the panels decreases in the late autumn, the floor will try to move the piano and book shelf closer to each other. If it does not succeed in this attempt, and it seldom does, undesired cracks will appear in the floor.
The above mentioned problems are solved through the present invention, whereby a joint profile for panels where a predetermined amount of expansion and contraction in the panels is absorbed in the joint is achieved. Accordingly the inventions deals with a joint profile intended to be arranged between panels. The joint profile comprises a first edge portion and a second edge portion. The invention is characterised in that the first edge portion comprises a main body portion, a bridge portion being at one end connected to the main body portion, said bridge portion further being provided with a distal edge and a connector means arranged close to the distal edge. The second edge portion is provided with a second main body portion comprising a connector receiving means. The main body portion is further provided with an edge portion having a geometry adapted for joining with a selected edge of the panels. The second main body portion is further provided with an edge member having a geometry adapted for joining with a selected edge of the panels.
The edge portion is preferably provided with joining means selected from the group consisting of; tongue, groove, undercut, protrusion, girder, web, lower cheek, upper cheek, resilient portion, hook, grapnel, claw and a combination thereof.
The edge member is preferably provided with joining means selected from the group consisting of; tongue, groove, undercut, protrusion, girder, web, lower cheek, upper cheek, resilient portion, hook, grapnel, claw and a combination thereof.
The connector means is suitably provided with a protruding lower end and that the connector receiving means are provided with a cavity intended for receiving the protruding lower end of the connector means. It is hereby suitable to make the connector means flexible. The connector receiving means is suitably so designed as to allow the connector means to flex angularly around a lower pivot point.
According to a preferred embodiment of the invention the connector receiving means is so designed as to allow the connector means to move, thereby allowing the bridge portion to move in a horizontal direction relative the second main body portion. The allowed horizontal movement results in a play which suitably is in the range 0.1-5 mm.
The portion arranged between the distal edge and an upper portion of the selected edge of the panels is suitably made resilient.
According to one embodiment of the invention a hollow space is formed under the bridge portion. This hollow space may then be used for arranging electrical cables, data cables, lighting, air evacuation or the like. The different elements of the joint profile are suitably made of thermoplastic material, thermosetting resin or metal such as aluminium. One suitable way of manufacturing such a profile is by extrusion. The profiles may be uniformly coloured, or even transparent (if made of plastic that is) but is of course possible to provide upper surfaces with any suitable decor. It is however suitable to provide the upper surface of the profile with a coating allowing it to match the wear resistance of the panels it is going to bridge. The edges of the profile designed to mate with edges of panels are suitably designed so that this joint becomes very tight and impenetrable to water and dirt. The remaining part of the joint profile is protected from the effects of water due to the fact that it can be made of materials like plastic or metal.
The invention also deals with a second preferred embodiment of the invention where a joint profile is intended to be arranged between panels. The invention is characterised in that a joint profile comprises a first edge portion, a second edge portion and a bridge portion.                The first edge portion comprises a first main body portion comprising a connector receiving means. The first main body portion is provided with an edge portion having a geometry adapted for joining with a selected edge of the panels.        The bridge portion is at one end connected to the first main body portion via a first connector means adapted to fit the connector receiving means. The bridge portion is further being provided with a second end being provided with a second connector means adapted to fit the connector receiving means.        The second edge portion is provided with a second main body portion comprising a connector receiving means. The second main body portion is provided with an edge member having a geometry adapted for joining with a selected edge of the panels.        
The edge portion is suitably provided with joining means selected from the group consisting of; tongue, groove, undercut, protrusion, girder, web, lower cheek, upper cheek, resilient portion, hook, grapnel, claw and a combination thereof.
The edge member is provided with joining means selected from the group consisting of; tongue, groove, undercut, protrusion, girder, web, lower cheek, upper cheek, resilient portion, hook, grapnel, claw and a combination thereof.
The first and second connector means is suitably provided with a protruding lower end and the connector receiving means are provided with a cavity intended for receiving the protruding lower end of the connector means.
The first and second connector means is suitably flexible. The connector receiving means is suitably so designed as to allow the first connector means to flex angularly around a lower pivot point. The connector receiving means is suitably so designed as to allow the also second connector means to flex angularly around a lower pivot point. The connector receiving means are preferably so designed as to allow the first and second connector means to move, thereby allowing the bridge portion to move in a horizontal direction relative the first and or second main body portion.
The allowed horizontal movement results in a play which suitably is in the range 0.1-10 mm.
This play is designed so that the distance between the mating surfaces is very small when the moisture level in the panel is at its highest practical level. The distance will be at its largest when the panel has low or no moisture content.
The herein described joint may be used on every panel and every edge thereof in a floor installation. However it is advantageous to use it only on portions thereof such as only every other, third, fifth or tenth panel and only on long side edges thereof. The joint can also be used as a design feature. It is through the present invention possible to achieve dilatation in a floating floor which is flush with the upper surface of the floor. This is highly desired.
The movement in each joint is of course depending on the maximum and minimum moisture levels in the panel as well as the distance between the joints according to the invention. However, an allowed movement of 1 mm/meter of panel is normally more than enough.
The joint profiles are suitably shaped as extended profiles which may be manufactured through extrusion which is a well known and rational method. The joint profiles are suitably shaped as extended lengths or rolls which can be cut to the desired length. The length of the joint profiles considerably exceeds the length of a floor element, before being cut. An advantage with such long profiles is that they can be laid over the whole width of the floor and will thereby reduce the risk for deviations and gaps in the floor since it bridges the lateral joints of the floor. Such bridging of the lateral joints can of course be used even if the joint profiles have the same length as, or is shorter than the floor elements. Shorter pieces of joint profiles is suitably used when it comes to the lateral joints of the floor.
Suitable materials are thermoplastic materials such as polyolefins, polystyrene, polyvinyl chloride or acrylnitril-butadiene-styrene-copolymer. These can suitably be filled with for example wood powder, lime or fibre such as glass fibre in order to increase the dimension stability. The top, visible surface of the joining profile may be decorated through any known means. It is however suitable to make this surface abrasion resistant enough to match the panels it is to be installed together with. It is also possible to make the joining profile of metal such as aluminium or steel. This profile may then be provided with a bellow-like structure to absorb the movement, have elastic portions of materials like rubber or being designed to bow downwards or upwards. It may be considered advantageous to design the portion arranged between the end of the bridge portion and an upper portion of the selected edge of the panels to be made resilient. This can for example be achieved by making this portion of an elastic material like rubber or the like. The elastic portion is then desiged so that it will be in full contact with the end of the bridge portion as well as the edge of the panel when the joint is fully extended. The elastic portion will then be compressed when the distance between the panels decrease.
Accordingly, FIG. 1 shows in cross-section a joint profile for panels according to a first embodiment of the present invention. FIG. 1 shows a joint profile 1 intended to be arranged between panels 2 and 3 respectively. The joint profile 1 comprises a first edge portion 10 and a second edge portion 11. The first edge portion 10 comprises a main body portion 101, a bridge portion 102 being at one end connected to the main body portion 101 said bridge portion 102 further being provided with a distal edge 103 and a connector means 104 arranged close to the distal edge 103. The second edge portion 11 is provided with a second main body portion 111 comprising a connector receiving means 114. The main body portion 101 is provided with an edge portion 105 having a geometry adapted for joining with a selected edge 2′, 2″, 3′ and 3″ respectively of the panels 2 and 3 respectively. The second main body portion 111 is provided with an edge member 115 having a geometry adapted for joining with a selected edge 2′, 2″, 3′ and 3″ respectively of the panels 2 and 3 respectively.